Acetic acid has a much stronger tendency to dimerize than any alcohol. Therefore, it is not reasonable to assume that K_a2 = K_a3 = … for acetic acid. The assumption is reasonable for K_a3 = K_a4 = …, however. We can supplement the theory by adding a single additional equation for the dimerization reaction with an effective equilibrium constant equal to the ratio of the true K_a2 divided by the linear association value. Assume that the linear association is negligible for the saturated vapor at ~300–350 K.

(a) Determine the value of K_a2 that matches the saturated vapor compressibility factor in that range. Let N_Aε_HB/R = 4000 K for the dimerization.

(b) Determine the values of K_AD, b, α_c ,ε_HB that match the critical point.

(c) Determine the values of K_AD, b, α_c ,ε_HB that match the vapor pressure at T_r = 0.7 for acetic acid.